DOI: 10.6060/tcct.20165912.5422
Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2016. V. 59. N 12. P. 118-126

The possibility of electrochemical purification of wastewaters containing azobenzene was studied. The electrolysis was carried out in the electrochemical cell with separated cath-ode and anode compartments and platinum electrodes. Firstly, the electrochemical behaviour of azobenzene at platinum electrode was investigated. The insertion of azobenzene in the 0.1 M solution of sulfuric acid led to the appearance of cathodic currents in the “hydrogen” re-gion of cyclic voltammograms (CVs). These currents corresponded to the electrochemical re-duction of azobenzene. It is important that these reactions occurred at the “hydrogen” region of potentials where the hydrogen adatoms existed at the surface of platinum. More likely, that the reduction of azobenzene proceeds through the interaction of hydrogen adatoms with azo-benzene molecules at the electrode surface. The “double-layer” region of CVs did not change significantly; the currents measured in it were less in comparison with pure solution of 0.5 M H2SO4. There were no sharp differences between the pure solution of sulphuric acid and so-lution containing azobenzene. Nevertheless, the visible disappearance of the color of azoben-zene was observed during the electrochemical treatment. Probably, the oxidation of azoben-zene was caused by the interaction of its molecules with the active forms of oxygen generat-ing at the platinum anode in the course of electrolysis. The particular attention was paid to the indentification of the products of electrochemical transformation. It was shown that the cathode reduction is not unsuitable for this purpose due to the formation of toxic benzidines in the solutions under treatment. This may be result of benzidine rearrangement which occurs in acid solutions. However, the use of neutral and alkaline solutions is impossible because the electroreduction of azobenzene does not take place under these conditions. The electrooxida-tion leads to formation of less toxic products. Among them the polyphenols have been sup-posed. Based on this fact the electrochemical oxidation may be considered as a possible technique for destruction of azobenzene.

Key words: wastewater treatment, azobenzene, electroreduction, electrooxidation, produts of re-duction and oxidation

1. Comninellis Ch., Chen G. Electrochemistry for the Environment. Ed. Springer Science+Business Media, LLC. 2010. 561 p.
2. Sequeira C.A.C. Environmental Oriented Electrochemistry. Elsevier Science B.V. 1994. 718 p.
3. Kariyajjanavar P., Jogttappa N., Nayaka Y.A. Studies on degradation of reactive textile dyes solution by electrochemical meth-od. J. Hazar Mater. 2011. V. 190. N 1–3. P. 952–961. DOI: 10.1016/j.jhazmat.2011.04.032.
4. Jović М., Stanković D., Manojlović D., Anđelković I., Milić A., Dojčinović B., Roglić G. Study of electrochemical oxidation of reactive textile dyes using platinum electrode. Int. J. Electrochem. Sci. 2013. V. 8. N 1. P. 168 – 183.
5. Zakaria K., Christensen P.A. The use of Ni/Sb*SnO2-based membrane electrode assemble for electrochemical generation of ozone and decolourisation of Reactive Blue 50 dye solutions. Electrochim. Acta. 2014. V. 135. P. 11-18. DOI: 10.1016/j.electacta.2014.05.013.
6. Kuznetsov V.V., Mikheeva E.N., Lyashenko S.E., Kolesnikov A.V. The electrooxidation of wastewater of dyes industry on pattern of Orange 2G dye removal. Voda. Khimiya i ekologiya. 2013. V. 3. P. 33-36 (in Russian).
7. Guivarch E., Trevin S., Lahitte C., Oturan M.A. Degradation of azo-dyes in water by Electro-Fenton process. Environ. Chem. Lett. 2003. V. 1. N 1. P. 38–44. DOI: 10.1007/s10311-002-0017-0.
8. Lund H., Hammerich O. Organic Electrochemistry. Fourth Edition. Marcel Dekker, Inc. 2001. 1347 p.
9. Yu H.-Zh., Wang Y.-Q.,. Cheng J.-Zn, Zhao J.-W., Cai Sh.-M., Inokuchi H., Fujishima A., Liu Zh.-F. Electrochemical behaviour of azobenzene self-assembled monolayers on gold. Langmiur. 1996. V. 12. N 11. P. 2843-2848. DOI: 10.1021/la950632c.
10. Komorsky-Lovric S., Lovric M. Measurements of red-ox kinetics of adsorbed azobenzene by a “quasireversible maximum” in square-wave voltammetry. Electrochim. Acta. 1995. V. 40. N 11. P. 1781-1785. DOI: 10.1016/0013-4686(95)00097-X.
11. Wang A., Qu J., Liu H., Ge J. Degradation of azo dye Acid Red 14 in aqueous solution by electrokinetic and electrooxidation process. Chemosphere. 2004. V. 55. N 9. P. 1189–1196. DOI: 10.1016/j.chemosphere.2004.01.024.
12. Liu R.-H., Li W.-W., Sheng G.-P., Tong Zh.-H., Lam M. H.-W., Yu H.-Q. Self-driven bioelectrochemical mineralization of azobenzene by coupling cathodic reduction with anodic inrtmediate oxidation. Electrochim. Acta. 2015.
V. 154. P. 294-299. DOI: 10.1016/j.electacta.2014.12.063.
13. Martınez-Huitle C. A., Ferro S. Electrochemical oxidation of organic pollutants for wastewater treatment: direct and undirect pro-cesses. Chem. Soc. Rev. 2006. V. 35. N 12. P. 1324–1340.: 10.1039/B517632H.
14. Simond O., Schaller V., Comninellis Ch. Theoretical model of anodic oxidation of organics on metal oxide electrodes. Electo-chim. Acta. 1997. V. 42. N 13-14. P. 2009-2012. DOI: 10.1016/S0013-4686(97)85475-8.
15. Scialdone O. Electrochemical oxidation of organic pollutants in water at metal oxide electrodes: A simple theoretical model includ-ing direct and indirect oxidation processes at the anodic surfaces. Electochim. Acta. 2009. V. 54. N 26. P. 6140-6147. DOI: 10.1016/j.electacta.2009.05.066.
16. Kuznetsov V.V., Kladiti S.Yu., Kapustin E.S., Kolesnikov V.A. Anodic crystallization of thallium and lead oxides modified by Mo(VI) species. Teor. Osnovy Khim. Tekhnol. 2015. V. 49. N 3. P. 239–245. DOI: 10.1134/S0040579515030070 (in Russian).
17. Oturan M.A., Sires I., Oturan N., Perocheau S., Laborde J.-L., Trevin S. Sonoelectro-Fenton process: A novel hydride tech-nique for destruction of organic pollutants in water. J. Electroanal. Chem. 2008. V. 624. N 1-2. P. 329–332. DOI: 10.1016/j.jelechem.2008.08.005.
18. Stergiopoulos D., Dermentzis K., Giannakoudakis P., Sotiropoulos S. Electrochemical decolarization and removal of Indigo Carmine textile dye from wastewater. Global NEST Journal. 2014. V. 16. N 3. P. 499-506.
19. Almomani F., Baranova E.A. Kinetic study of Electro-Fenton oxidation of azo-dyes on boron-doped diamond electrode. Environ Technol. 2013. V. 34. N 11. P. 1473-1479. DOI:10.1080/09593330.2012.758644.
20. Yue L., Guo J., Yang J., Lian J., Luo X., Wang X., Wang K., Wang L. Studies of electrochemical oxidation of Acid Orange II wastewater with cathodes modified by quinones. J. Ind. Eng. Chem. 2014. V. 20. N 3. P. 752`-758. DOI: 10.1016/j.jiec.2013.06.003.
21. Tomilov A.P., Mairanovskiy S.G., Fioshin M.Ya., Smir-nov V.A. Electrochemistry of organic compounds. L.: Khimiya. 1968. 592 с.
22. Ramírez C., Saldaña A., Hernández B., Acero R., Guerra R., Garcia-Segura S., Brillas E., Peralta-Hernández J.M. Electro-chemical oxidation of methyl orange azo dye at pilot flow plant using BDD technology. J. Ind. Eng. Chem. 2013. V. 19. N 2. P. 571-579. DOI: 10.1016/j.jiec.2012.09.010.
23. Kiper R.A. Physico-chemical properties of substances. Handbook on Chemistry. Khabarovsk. 2013. 1016 p. (in Russian).
24. Holcapek M., Volna K., Vanerkova D. Effect of functional groups on fragmentation of dyes in electrospray and atmospheric pressure chemical ionization mass spectra. Dyes and Pigments. 2007. V. 75. N 1. P. 156-165. DOI: 10.1016/j.dyepig.2006.05.040.
25. Sadler J.L., Bard A.J. The electrochemical reduction of azo compounds. J. Amer. Chem. Soc. 1968. V. 90. N 8.
P. 1979-1989. DOI: 10.1021/ja01010a010.
26. Kuznetsov V.V., Kladiti S.Yu. Filatova E.A., Kolesnikov A.V. Electrochemical behavior of manganese and molybdenum an-odes in chloride and sulfate-containing solutions. Mendeleev Communications 2014. V. 24. N 6. P. 365-367. DOI: 10.1016/j.mencom.2014.11.019.
27. Toxicological Profile for Benzidine. U.S. Department of Health and Human Services. 2001.

2016, Т. 59, № 12, Стр. 118-126


You will get the pdf-copy of your article by e-mail